* Basalt: This is a dark-colored, fine-grained rock that is very common. It forms from the rapid cooling of lava flows.
* Rhyolite: This is a light-colored, fine-grained rock that is rich in silica. It forms from the explosive eruptions of volcanoes.
* Andesite: This is an intermediate-colored, fine-grained rock that is often found in volcanic arcs. It forms from the cooling of lava flows that have a higher silica content than basalt.
* Obsidian: This is a dark, glassy rock that forms when lava cools very quickly. It is often found in volcanic flows and is used for tools and jewelry.
* Pumice: This is a light, porous rock that forms from the rapid cooling of lava that is rich in gas. It is often used in gardening and as a scrubbing agent.
These are just a few examples of the many types of extrusive igneous rocks that can be found on the Earth's surface. They are a fascinating reminder of the Earth's dynamic processes and the power of volcanoes.